Mr Posen, a member of the Bank's nine-strong Monetary Policy Committee, added that banks were making "excuses" for their failure to lend to small businesses, suggesting the real reason might be that they are "reluctant, risk-averse jerks".

Speaking to Sky News, he said: "We, the British taxpayer, but also the British government as a regulator, is not getting value for money because the role of banks ... is to provide credit for growth of the real economy in the UK and they are not doing the job.

"We've got to change the competitive pressures on them, change the rules on them so they're forced to do the job right."

Official figures show that small businesses repaid 6.1pc of their outstanding debts to the banks over the past year as the cost of borrowing became more expensive. Mr Posen claimed that the decline in borrowing by small businesses was not due to lack of demand, as the banks have claimed, but to the higher cost.

"When banks say it's all about no demand [for loans], that's crazy," he told BBC Radio's Wake up to Money. "Fees, prices and spreads on loans going to small businesses are going up, and normally prices don't go up when demand is falling."

He added that banks were using new capital and gearing requirements as an excuse to limit lending. "They are not being forced to build up capital and cut back their balance sheets as much as they claim... It's an excuse, it's not a reality," he said.

To explain their behaviour, he wondered whether bankers were "reluctant, risk-averse jerks" or if there was a more fundamental problem.

He claimed banks were choosing to roll over loans to big businesses rather than make new loans to smaller firms and stressed that the problem was particularly acute in the UK due to the lack of alternative funding for small businesses. He urged the Government to press ahead quickly with its credit easing programme to get £20bn into the sector.

"Back in October we heard Vince Cable and the Chancellor talk about credit easing to their party conferences ... but we haven't seen the structural changes to go with it," Mr Posen said.

He also hinted that he will be voting for more money printing next week when the MPC meets to decide on interest rates and quantitative easing (QE). "I'm certainly leaning toward doing more QE if we don't change the forecast," he told Bloomberg Television. He added: "£75bn was a good slug last time and there's a case to do it again."

Mr Posen voted to increase QE for a year before the other MPC members joined him in October. The Bank is expected to top up the £75bn second round with another £50bn-£75bn next week. The first round of QE totalled £200bn.

He added that he was "slightly more optimistic than I was a few months ago" despite the ongoing eurozone crisis.